test: drop ssh-gate suites and shadow-route assertions (PRD 0009)

- Delete tests/unit/test_ssh_gate.py and the fixture_with_ssh helpers.
- test_pipelock_yaml: drop the ssh-leak guard (structurally
  impossible now); the remaining tests switch to fixture_minimal.
- test_pipelock_allowlist: rewrite the union/dedup test to
  exercise an egress.allowlist that duplicates a baked default
  (the property the ssh-leak assertion was hitching onto).
- test_manifest_git: shadow-route assertion becomes a legacy-ssh-
  dies-with-hint assertion, since bottle.ssh is now parse-fail.
- test_orphan_cleanup: drop the SSHGate.stop idempotency check;
  pipelock equivalent stays.
- test_dry_run_plan: drop assertions on the removed ssh_hosts /
  ssh_gate keys.

52 unit tests pass.

tests/integration/test_dry_run_plan.py

@@ -79,8 +79,6 @@ class TestDryRunPlan(unittest.TestCase):
             self.assertEqual("runc", plan["runtime"],
                              "runsc isn't available on the CI runner")
             self.assertEqual([], plan["skills"])
-            self.assertEqual([], plan["ssh_hosts"])
-            self.assertEqual([], plan["ssh_gate"])
             self.assertEqual([], plan["git_remotes"])
             self.assertEqual([], plan["git_gate"])
             self.assertEqual(False, plan["remote_control"])

tests/integration/test_orphan_cleanup.py

@@ -1,8 +1,8 @@
 """Integration: the cleanup primitives the start-flow trap depends on
 are idempotent. The original orphan-network bug was a trap-ordering
 issue; the fix moved the install earlier. The trap is only safe if
-network_remove, PipelockProxy.stop, and SSHGate.stop are no-ops
-against missing resources."""
+network_remove and PipelockProxy.stop are no-ops against missing
+resources."""
 
 import os
 import subprocess
@@ -17,10 +17,6 @@ from claude_bottle.backend.docker.pipelock import (
     DockerPipelockProxy,
     pipelock_container_name,
 )
-from claude_bottle.backend.docker.ssh_gate import (
-    DockerSSHGate,
-    ssh_gate_container_name,
-)
 from tests._docker import skip_unless_docker
 
 
@@ -79,13 +75,6 @@ class TestOrphanCleanup(unittest.TestCase):
         # Should not raise.
         DockerPipelockProxy().stop(pipelock_container_name(f"missing-{self.slug}"))
 
-    def test_ssh_gate_stop_missing_sidecar(self):
-        # Same trap-safety requirement for the gate (PRD 0007). The
-        # launch ExitStack calls gate.stop on every error path; if
-        # the container was never created (early failure), stop must
-        # still no-op.
-        DockerSSHGate().stop(ssh_gate_container_name(f"missing-{self.slug}"))
-
 
 if __name__ == "__main__":
     unittest.main()